Traditional railing assemblies are comprised of vertically oriented pickets attached by one or more rails. While the pickets penetrate intermediate level rails, they often do not penetrate the top rail. In many railing configurations the top rail is intended to be gripped by a user in order to provide stability to the user.
One objective of the improved railing assembly described herein is to provide a top rail subassembly for a railing assembly. In other words, the railing assembly has as one of its components a top rail subassembly. One of the components of the top rail subassembly is a top rail. The railing assembly should be capable of maintaining a range of picket to top rail angles. This allows the railing to be installed upon sloped terrain with the pickets vertically oriented and the rails parallel to the sloped terrain. Others have accomplished this objective by using multi-component rail assemblies. One of the components is pivotally attached to the pickets. The second component (i.e., an upper rail component) is pivotally attached to the first component. For example, see U.S. Pat. No. 6,752,385 issued to Zen et al. and U.S. Pat. No. 7,384,025 issued to Lo.
The improved railing assembly described herein has a number of advantages compared to prior art railing assemblies. It allows a visible top rail to slide relative to a hidden inner rail. This allows enhanced outer rail to picket angle adjustability. The fasteners attaching the hidden inner rail to the pickets are hidden from view and contained within a recess within the inner rail. The bottom of the top rail subassembly is covered by a bottom rail. This limits the ability of contaminants to enter into the sliding interfaces between the components. The bottom rail also provides a structure from which stiffeners project. Stiffeners on the top rail and the bottom rail interface with each other or with a seat on the inner rail in order to provide enhanced structural stability. Further, the top rail and the inner rail releasably snap together to provide quick and easy installation, as well as disassembly of the components. The top rail, inner rail and bottom rail configurations are such that they may be fabricated by an extrusion process such as aluminum extrusion.